EP0166482A2 - Verfahren zur Gewinnung von Metallen aus ihren Halogeniden - Google Patents

Verfahren zur Gewinnung von Metallen aus ihren Halogeniden Download PDF

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Publication number
EP0166482A2
EP0166482A2 EP85200907A EP85200907A EP0166482A2 EP 0166482 A2 EP0166482 A2 EP 0166482A2 EP 85200907 A EP85200907 A EP 85200907A EP 85200907 A EP85200907 A EP 85200907A EP 0166482 A2 EP0166482 A2 EP 0166482A2
Authority
EP
European Patent Office
Prior art keywords
silicon
mixture
sodium fluoride
container
metal halide
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP85200907A
Other languages
English (en)
French (fr)
Other versions
EP0166482A3 (de
Inventor
Kenneth M. Sancier
Angel Sanjurjo
Robert M. Emerson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Anic SpA
Agip SpA
Original Assignee
Anic SpA
Agip SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Anic SpA, Agip SpA filed Critical Anic SpA
Publication of EP0166482A2 publication Critical patent/EP0166482A2/de
Publication of EP0166482A3 publication Critical patent/EP0166482A3/de
Withdrawn legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/02—Silicon
    • C01B33/021—Preparation
    • C01B33/027—Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material
    • C01B33/033—Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material by reduction of silicon halides or halosilanes with a metal or a metallic alloy as the only reducing agents
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B34/00—Obtaining refractory metals
    • C22B34/10—Obtaining titanium, zirconium or hafnium
    • C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
    • C22B34/1263—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining metallic titanium from titanium compounds, e.g. by reduction
    • C22B34/1268—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining metallic titanium from titanium compounds, e.g. by reduction using alkali or alkaline-earth metals or amalgams
    • C22B34/1272—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining metallic titanium from titanium compounds, e.g. by reduction using alkali or alkaline-earth metals or amalgams reduction of titanium halides, e.g. Kroll process
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B34/00—Obtaining refractory metals
    • C22B34/10—Obtaining titanium, zirconium or hafnium
    • C22B34/14—Obtaining zirconium or hafnium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B5/00—General methods of reducing to metals
    • C22B5/02—Dry methods smelting of sulfides or formation of mattes
    • C22B5/04—Dry methods smelting of sulfides or formation of mattes by aluminium, other metals or silicon

Definitions

  • That process is primarily exemplified by the description of specific reactions that produce silicon.
  • the product element is silicon and in that case silicon fluoride is prepared from an aqueous solution of fluosilicic acid, a low cost waste by-product of the phosphate'fertilizeriindustry by treatment with a metal fluoride which precipitates the corresponding fluosilicate. This salt is filtered, washed, dried and thermally decomposed to produce the corresponding silicon tetrafluoride and metal fluoride which can be recycled to the precipitation step.
  • the silicon tetrafluoride is then reduced by a suitable reducing metal of the group IA, IIA or IIIA of the Mendelean periodic Table and the products of the reaction are elemental silicon and a metal fluoride of groups IA, IIA and IIIA which are treated to extract the silicon.
  • the present invention is directed to the part.of the process which deals with the manner of continously or intermittently removing the products of reaction (Si and NaF) produced by the reaction between SiF 4 and an alkali reducing metal (eg. Na) from a reactor or container and the subsequent separation of elemental silicon product.
  • Si and NaF products of reaction
  • an alkali reducing metal eg. Na
  • reaction products produced by the systems disclosed in the patents are in a form that is difficult to remove from the reactor or container in which they are formed or stored.
  • separation and removal techniques that tend to introduce impurities are distinctly disadvanteageous.
  • Metals such as Ti also have stringent purity requirements. High impurity contents result in a loss of certain-mechanical properties.
  • the present invention is specifically concerned with the separation of the reaction products produced by reaction of Na and SiF 4 .
  • the reaction is performed in a container configured in such a manner that at least a portion of the sodium fluoride is melted and removed from the reaction mixture.
  • the present invention is concerned with an improved process for the recovery of elemental silicon or transition metals such as titanium zirconium or hafnium from a reaction mixture which contains a metal halide and the elemental form of Si or a transition metal.
  • the process comprises (a) maintaining the reaction mixture in a container at a temperature that liquifies at least a portion of said metal halide; (b) removing at least a portion of the liquid metal halide from said container; (c) removing from said container with pressure or vibration a portion of the mixture from which a portion of the metal halide has been removed; and (d) recovering the balance of said silicon or transition metal from said reaction mixture.
  • reaction mixtures which comprise a metal halide and elemental silicon or transition metal from a container by means that include a step wherein mechanical force is applied to the container which holds the reaction mixture.
  • FIG. 1 is a cross-section of an apparatus that may be utilized in practice of the present invention.
  • the improved recovery process of the invention is carried out in any suitable apparatus which may be used to contain the hot reaction mixture that is obtained by the reduction of a reactant: silicon halides or transition metal halides with a reducing metal.
  • the apparatus may be an integral zone of a reactor in which the reduction reaction is carried out batchwise or continuously.It may be a separate apparatus which is used only a separator.
  • the essential feature is that the apparatus should be provided with heating means to liquefy at least a portion of the product metal halide in the reaction mixture and optionally have means for permitting selective removal of at least a portion of liquid product metal halide while retaining the Si or transition metal product and the balance of the product metal halide.
  • the process is based on the fact that the product metal halide is a low viscosity liquid at a temperature below the temperature at which the elemental Si or transition metal product exhibits any substantial flow properties.
  • the melting points are about 988°C and 1412°C. This temperature differential permits sufficient heat to be applied to permit liquid sodium fluoride to be drained off through any suitable opening, in substantially pure form free of silicon particles.
  • Heat may be applied by means such as resistance heaters, or more preferably by radio frequency induction heating.
  • Temperatures of 1000°C to 1400°C may be used with mixtures of silicon and sodium fluoride, and more preferred temperatures are from 1050°C to 1250°C.
  • the substantially pure sodium fluoride may be recycled upstream in an integrated production facility to serve as a source for sodium fluoride that may be used to make fluosilicate.
  • the purity of the recycled sodium fluoride is a special advantage that can be utilized in making sodium fluosilicate.
  • the present invention also contemplates the use of mechanical force to aid in the removal of reactants from the container.
  • the mechanical force may be applied directly by electricity or pneumatically activated pistons, rods or other suitably shaped contact means directly to the reactants to expel said reactants.
  • indirect mechanical force may be applied by electrically or pneumatically activated vibrators, shakers or other agitator means.
  • a further means may be through the use of positive or negative pressure which may be applied to cause all or a portion of the reactants to be ejected from the container in which they are held.
  • Argon gas may be used for this purpose or a vacuum may be applied.
  • FIG. 1 A preferred, but not exclusive, embodiment of the reactor design is shown in FIG. 1 for better illustration.
  • the sodium fluoride is obtained in a weight ratio of 6:1 of sodium fluoride to silicon. Of the six parts of sodium fluoride present, it is possible to remove about a maximum of five parts of liquid sodium fluoride from the container. Subsequent removal is done by aqueous leaching or by melt separation. The size of the orifice through which the sodium fluoride is selectively removed is important. Experimental data show that an orifice of 0.1 cm in diameter will prevent the flow of liquid sodium fluoride at 1425°C while an orifice of 0.26 cm in diameter is necessary for molten sodium fluoride to flow.
  • a mixture of sodium fluoride and silicon was placed in a graphite crucible and pressure was applied using two different methods: mechanically with a graphite rod and with argon gas to the top of the reactor.
  • a graphite rod having a diameter of 0.9 cm was pressed down through a graphite crucible 7.5 cm high by 3 cm in diameter having a lower portion constricted to an outlet of 2 cm in diameter by tapering the internal walls inwardly at an angle of 130°.
  • the rod was passed down into a 2:1 mixture of sodium fluoride and silicon causing the slurry product to flow out through the orifice into a lower reception crucible.
  • experiment 2 a rod having a lower flat surface of 2.5:cm in diameter was used, in the same crucible as in experiment 1 with the same material used in experiment 1, at a temperature of about 1400°C.
  • the material obtained from the crucible was substantially pure sodium fluoride and the silicon was retained in the crucible.
  • experiment 3 argon was used in the same crucible that was used in experiment 1 but the temperature was 1100°C. A pressure of 0.07 atm of argon was used. The use of gas pressure was successful in discharging the product but the product around the central axis was discharged preferentially with respect to the product near the walls.
  • the discharged slurries dripping into the lower reception crucible behaved like liquids that wet graphite walls.
  • Aqueous leaching may be used to selectively remove the water soluble sodium fluoride from the insoluble silicon although other separation techniques may be utilized.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Manufacturing & Machinery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Silicon Compounds (AREA)
EP85200907A 1984-06-26 1985-06-10 Verfahren zur Gewinnung von Metallen aus ihren Halogeniden Withdrawn EP0166482A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US62457484A 1984-06-26 1984-06-26
US624574 1990-12-10

Publications (2)

Publication Number Publication Date
EP0166482A2 true EP0166482A2 (de) 1986-01-02
EP0166482A3 EP0166482A3 (de) 1988-11-23

Family

ID=24502509

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85200907A Withdrawn EP0166482A3 (de) 1984-06-26 1985-06-10 Verfahren zur Gewinnung von Metallen aus ihren Halogeniden

Country Status (4)

Country Link
EP (1) EP0166482A3 (de)
JP (1) JPS6115931A (de)
KR (1) KR860000398A (de)
IN (1) IN165106B (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2012086544A1 (ja) * 2010-12-20 2014-05-22 三菱化学株式会社 シリコンの製造方法及び製造装置、シリコンウェハー、並びに、太陽電池用パネル

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2564337A (en) * 1948-11-02 1951-08-14 Battelle Development Corp Production of refractory metals
US2676882A (en) * 1950-05-31 1954-04-27 Kennecott Copper Corp Method for recovering refractory metals
US2763480A (en) * 1950-07-28 1956-09-18 Nat Lead Co Apparatus for producing refractory metals
US4442082A (en) * 1982-12-27 1984-04-10 Sri International Process for obtaining silicon from fluosilicic acid

Also Published As

Publication number Publication date
KR860000398A (ko) 1986-01-28
EP0166482A3 (de) 1988-11-23
IN165106B (de) 1989-08-19
JPS6115931A (ja) 1986-01-24

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